Lifetime Analysis of GaN-Based Power Converters for Battery Charging Applications

Abstract

Gallium Nitride (GaN) devices are gaining popularity over silicon devices because of their high efficiency, high power density, and high-temperature operational capability. In addition to this, GaN devices reduce the converter filter size requirement owing to the high-frequency operation capability of these devices. However, the application-specific reliability of these devices is still unknown. As the GaN is the recently developed device for medium (>500W) power applications compared with Si/SiC devices. Hence, to use these devices in power converters the reliability of these devices needs to be analyzed before they can be used in power converters. However, GaN devices have a unique structure, which demands a novel reliability analysis method. As a result, a unique reliability analysis approach for determining the lifetime of a GaN converter is proposed in this paper. A GaN-based synchronous buck converter for battery charging applications is demonstrated in this paper to verify the proposed method. This method can assess the impact of different charging profiles on the GaN-based converters' switching lifetime. Hence, the lifetime of the synchronous buck converter is calculated separately using the constant current constant voltage (CCCV) and multi-step constant current (MSCC) charging methods. It was discovered that although the MSCC profile reduce battery charging time but the switching lifetime of the GaN switch is 2.2 times lower as that of the CCCV charging method. The complete mathematical analysis and simulation results are included in this paper.